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Slide Rules

Index by Makers & Retailers

Hundreds of companies around the world were involved in the production of slide rules from the 18th to the 20th centuries. Click on one of the names below to see the objects in this collection that were associated with that firm.

This ten-inch one-sided wooden slide rule is coated with white celluloid. The indicator is glass with white plastic edges attached by metal screws. The base has A, D, and K scales. The slide has B, CI, and C scales on one side of the slide and S, L, and T scales on the other side. The top and bottom edges are beveled; the top has a simply divided scale 10 inches long and divided to sixteenths of an inch, while the bottom has a simply divided scale 25 centimeters long and divided to millimeters.

Keuffel & Esser made slide rules of this type from 1909 to 1967. McCoy notes that this version of model 4053-3 (with this model number and the engraved tables) was introduced in 1954. In 1959, the rule sold in a plain case for $13.50. In 1962, model number 4053-3 was changed to 68-1622. The serial number suggests a date closer to the late 1950s than to the early 1960s. Compare to the earlier rule, 1981.0933.05.

This ten-inch one-sided mahogany slide rule is coated with white celluloid. The top is beveled and bears a scale of nine inches whose ends may have broken off. The base has A, D, and K scales. The slide has B, CI, and C scales on one side and S, L, and T scales on the other side. The indicator is glass with plastic edges held together with metal screws. The top plastic edge is broken. The front edge of the rule has a scale of 25 centimeters. A paper table of equivalents and slide rule settings, based on U. S. Bureau of Standards Circular No. 47, is pasted to the back of the rule. Compare the table to 1999.0254.01.

The top of the base is marked in red: PAT. JUNE 5, 1900; KEUFFEL & ESSER CO. N.Y.; MADE IN U.S.A. The right end of the slide is marked in red: < N4053-3 >. The left end of the other side of the slide and the scale of centimeters have the serial number: 350305. The top of the base and under the slide are scratched with the initials: PML. The bottom plastic edge of the indicator is marked: PATENT 2,086,502, with K&E CO. N.Y., on the back of the edge.

Keuffel & Esser of New York sold this slide rule as model N4053-3 from 1925 through 1953. Illustrations in K&E catalogs include the patent date of June 5, 1900, from 1925 through 1934. The serial number suggests the rule was made closer to 1934. However, the patent on the indicator was issued in 1937, suggesting that this part was replaced after the rule was purchased. Compare to 1981.0922.08.

William J. Ellenberger (1908–2008) donated this object. He studied electrical and mechanical engineering at The George Washington University between 1925 and 1934. He then worked for the Potomac Electric Power Company and the National Bureau of Standards. During World War II, he served in the U.S. Army Signal Corps. He was a civilian construction management engineer for the army from 1954 to 1968, when he became a private consultant.

This ten-inch mahogany linear slide rule is coated with white celluloid on the front and both sides of the slide. The base has A and D scales. The slide has B and C scales on one side and S, L, and T scales on the other. A paper table of equivalents and slide rule settings, based on U. S. Bureau of Standards Circular No. 47, is pasted to the back of the rule. See also 2001.0117.01. According to Eric Marcotte, this circular was in force from 1914 to 1936. Keuffel & Esser included it on slide rules from the 1920s to the 1950s.

The indicator is glass with a plastic frame, of the style used by Keuffel & Esser between 1915 and 1937, based on the patent indicated by the mark on the top edge of the frame: K&E.CO.N.Y. (/) PAT.8.17.15. The top of the base is marked in red: PAT. JUNE 5, 1900; KEUFFEL & ESSER CO. N.Y.; MADE IN U.S.A. For more on this patent, see MA*322761. Four expressions have been scratched into the front of the slide: x = A + B; ÷ = A – B; x – 1; ÷ + 1. The model number is printed at the right end in red: < 4055 >. The left end of the back of the slide and the front left corner of the base are marked with a serial number: 190673.

The rule is in a cardboard case covered with black morocco leather and heavily taped. It is marked: KEUFFEL & ESSER (/) FAVORITE (/) SLIDE RULE (/) 4055. It is also marked on the tape near one end: E. HELLER (/) ΣΦΕ. On the other side of that end, it is marked on the tape: PROPERTY OF (/) PETER (/) HELLER. K&E sold model 4055 from 1927 to 1943; the serial number suggests a date closer to 1927, when the instrument sold for $4.00. One owner of this slide rule was the mechanical engineer Edward Lincoln Heller (1912–2007), who received a BSfrom Lehigh University in 1934 and an MBA from Harvard University in 1939. It seems likely that he used the slide rule as a college student.

This two-sided white plastic circular slide rule helped railroad procurement officers determine the amount and cost of coal or oil needed to efficiently operate the boiler of a train engine. It consists of three concentric discs, with the two smaller discs on the front and back and one large disc in the middle. The metal fastener holding the discs together is tarnished. On the front, the outer edge of the large disc bears an evenly-divided scale for "Fuel Cost per Million Btu's and Steam Cost per 1000 lbs." The smaller disc has scales for coal cost per ton/oil cost per gallon, BTUs per pound, and evaporation for a high viscosity of fuel. A bell-shaped indicator has a scale for the weight of oil in pounds per gallon.

On the back of the instrument, from the outside in, there are scales and windows for reading the feed water temperature (in degrees Fahrenheit), difference in height (in BTUs per pound), steam pressure (in pounds per square inch), boiler efficiency, the heat value of fuel (in BTUs per pound), a boiler at high pressure, the factor of evaporation and equivalent evaporation, saturated steam pressure (in degrees Fahrenheit), and steam pressure (in pounds per square inch). There is a hairline indicator. The instrument fits into a black leather case.

The front of the device is marked: FRED Q. SAUNDERS (/) RICHMOND, VIRGINIA; FUEL-STEAM CALCULATOR; PAT. 2,328,881. The indicator on the front is marked: N & W (/) Ry. (/) CARRIER OF (/) FUEL SATISFACTION. This is the logo for the Norfolk & Western Railway, which transported coal east from the Pocahontas Coal and Coke Company in the Appalachian mountains. N&W was a relatively small railroad with a significant role in American transportation in the 19th and 20th centuries. It expanded into other activities in 1964 by merging with several other railroads; around this time, it also completed the transition from steam-powered to diesel locomotives. In 1998, the company was merged into Norfolk Southern Corporation.

Inside one of the windows on the back of the instrument is marked: 459; WHITEHEAD-HOAG, NEWARK, N.J. Founded in 1892 and in business until 1959, Whitehead and Hoag was a major producer of paper and plastic advertising novelties. Headquartered in Newark, it had branch offices in about thirty cities around the world. For other slide rules made by this company, see 1987.0221.02 and those described by the MIT Museum and Dick Rose's Catalog for Vintage Instruments (October 2000) at their web sites.

Besides his patent on this device, Fred Q. Saunders of Richmond, Va., copyrighted a "Fuel Steam Calculator Manual" on July 2, 1945 (cit. no. 21463). In 1952, he received patent no. 2,763,873 for a portable, collapsible bath tub to be used on hospital beds.

This ten-inch wooden linear slide rule is painted white. The indicator is frameless plastic. The base has A, D, and K scales. The slide has B, CI, and C scales on one side and S, L, and T scales on the other side. The back of the rule is printed with a table of equivalents and abbreviations, based on National Bureau of Standards Circular No. 47. Compare to 1984.1068.01. The back is marked: KEUFFEL & ESSER CO.; BEGINNER'S SLIDE RULE. N4058W; MADE IN U. S. A. There is no serial number. The case is green leatherette and is marked: K+E.

In 1897, Keuffel & Esser began to sell a slide rule for students. It was constructed inexpensively and was intended to be replaced once students had mastered the basic operations. The version with this model number and these scales was offered between 1944 and 1959, although the all-plastic indicator was not introduced until 1954. Model N4058W sold for $2.50 in 1959. Longtime NMAH staff member Barbara Coffee donated this example to the Smithsonian.

This instrument consists of a plastic disc riveted to a plastic base. It is very similar to a paper instrument of the same name (see 1987.0221.01).

The base, just outside the disc, has a logarithmic scale that represents readings in feet of a stadia rod used with a transit telescope. The base, just outside the disc, has a logarithmic scale that represents readings in feet of a stadia rod used with a transit telescope. The edge of the disc has two scales of functions of angles. Applying the first scale multiplies the stadia reading by 1/2 sin 2A, where A is the vertical angle of the transit telescope. This multiplication gives the difference in elevation of the transit and the stadia rod, in feet. The second scale multiplies the stadia reading by the square of cos A, to find the horizontal distance of the rod in feet.

The back of the instrument bears an advertisement for W. & L. E. Gurley, a maker of instruments in Troy, N.Y. A transit is depicted; it appears to be Gurley's Explorers [sic] precise transit. This was the smallest and lightest Gurley transit, shown in the Gurley catalogs for 1910 and 1912 (with a different image than is on this rule) and 1921 (with same image as on rule), but not the 1928 catalog. The 1921 catalog advertises the celluloid form of the Cox stadia computer and indicates that it sold for 75 cents.

A maker's mark at the bottom of the back of the computer is not legible, but the firm of Whitehead and Hoag of Newark, N.J., is known to have manufactured the instrument for Gurley in the second quarter of the 20th century.

This linear slide rule reflects changes that occurred in the materials of American manufacturing in the late 19th and early 20th centuries. The instrument itself has a pyroxylin (celluloid) envelope with a paper slide. There is no indicator. It was designed for use in computing the properties of belting used in industrial processes. At that time, such belting was typically made from one of three materials: canvas saturated with a liquid, leather, or rubber. The Boston chemical firm of J. A. and W. Bird and Company developed a new material that they called "Bird's Bull's Eye Belting," which consisted of canvas plies stitched together, with a gum base pressed around each cotton fiber. The maker claimed that this belting did not dry out (as the usual form of canvas belting did), resisted damage from fumes or humidity, and maintained its tension.

This instrument has two sides. The front, or "Computer for Belting," allows the user to find the revolutions per minute of a pulley, the speed of the belt in feet per minute, and the proper belt width for the horsepower, given the diameter of the matched pulley and its revolutions per minute. The back, or "Computer for Shafting" side, allows calculation of the horsepower a shaft can communicate, given the shaft's diameter and revolutions per minute. The calculation is made using Thurston's formula, which states that the horsepower equals the cube of the shaft diameter times the number of times it revolves per minute divided by a constant dependent on the nature of the shaft.

The instrument is marked on the front: COPYRIGHTED 1908 (/) BY J.A. & W. BIRD & CO. (/) ALL RIGHTS RESERVED BOSTON, MASS. On the back, it is marked near the left center in very small letters: PAT. JUNE 6, 1905. (/) THE WHITEHEAD & HOAG CO. NEWARK, N.J. Whitehead & Hoag manufactured a variety of plastic products including slide rules; see 1984.1080.01, 1987.0221.02, and 1988.0350.01 (which is also a belting computer).

Leather belting produced from cowhide tanned in a solution with ground oak bark had been manufactured in New York City from the 19th century. By the end of the century, the firm of Fayerweather & Ladew in Glen Cove, N.Y., had developed methods of waterproofing leather belting so that it could be used in wet and humid conditions. After the death of Edward R. Ladew in 1905, the firm operated as Estate of Edward R. Ladew. It was renamed Edw. R. Ladew Co., Inc., about 1919, and in 1920 it was sold to Graton & Knight Manufacturing Co. of Worcester, Mass.

To publicize its products, the company began distributing the Ladew Belting Strength Computer in 1914. This tan circular slide rule was made by the Whitehead & Hoag Company of Newark, N.J., under a June 6, 1905, patent for printing on pyroxylin (celluloid). It has a rotating disc and another rotating circular segment, pivoted about a metal rivet and attached to a rectangular celluloid base. The logarithmic scales allow computation of the horsepower a leather belt of known quality will transmit, given the width of the belt, the diameter of the pulley, and the rate of revolution of the pulley. The scales also make it possible to calculate the working strain of the belt, according to the kind of belt used and the horsepower transmitted. Instructions are provided on the back of the instrument.

For a linear slide rule for computations relating to cloth belting, see the Computer for Belting and Computer for Shafting made by J. A. & W. Bird & Co. of Boston (1988.0323.02). For information on Whitehead & Hoag, see 1984.1080.01.

This inexpensive one-sided white plastic slide rule has A, D, and K scales on the base, with S, L, and T scales on one side of the slide and B, CI, and C scales on the other side of the slide. The indicator is clear frameless plastic. The top of the base is marked: SP [inside a circle] PRECISION STERLING SLIDE RULE MADE IN U.S.A. The logo was trademarked by Sterling Plastics Company of Mountainside, N.J., in 1945. A clear plastic case has blue endpieces and is stamped 99¢.

According to Peter M. Hopp, Sterling began making slide rules in 1961. The company ceased producing slide rules around 1972. Since there are only two bridges holding the base together instead of five, Konshak suggests this example was made early in this time period. This example is probably model number 584. The Precision line came in various forms, as other examples have rulers on beveled edges, red scales, or green slides or bases. These were often sold as model number 685. For instructions, see 1988.0807.05. For company history, see 1998.3104.01.

ID number 1988.0807.01 was received with this flyer, which is marked on the front: STERLING SLIDE RULE A QUALITY INSTRUMENT FOR (/) STUDENT OR PROFESSIONAL (/) OPERATING INSTRUCTIONS (/) A complete course in use and operation of slide rule [sic]. The instructions cover multiplication and division, the CI scale (which is called the C1 scale), squares (the A and B scales) and square roots, and the K, L, S, and T scales. The back of the flyer is marked: STERLING PLASTICS CO. (/) MANUFACTURERS OF QUALITY SCHOOL SUPPLIES (/) 1140 Commerce Avenue, Union, New Jersey. The company logo (the letters SP inside a clear circle that is in turn inside a square formed of horizontal lines) is to the left of the mark. Sterling Plastics, whose main factory was in Mountainside, N.J., sold a variety of inexpensive plastic slide rules for students in the 1960s and 1970s.